So, then, would a good suggestion to this discussion be to have gameplay modes (like Original Sin 2), for example, where "classic" would be strict on 5e rules but "adventure" allows for some extraordinary rule bending?

I think an appropriate word for your third case is a**hole. Interestingly, if I were to tell people that the game is just going to be the way it is and they have to just "deal with it" that word could be applied to me.